Coupler for crank shaft grinder



Filed Sept. 21, 1953 R. A. FARNAM COUPLER FOR CRANK SHAFT GRINDER 2 Sheets-Sheet l INVENTOR.

RoY' A. FARNAM Dec. 4, 1956 R. A. FARNAM 2,772,527

COUPLER FOR CRANK SHAFT GRINDER Filed Sept. 21, 1953 2 Sheets-Sheet 2 INVENTOR.

ROY A. FARNAM ATTY.

United States Patent COUPLER FOR CRANK SHAFT GRINDER Roy A. Farnam, La Grande, Oreg.

Application September 21, 1953, Serial No. 381,169

3 Claims. (Cl. 51-237) This invention relates to the grinding of crank shafts of automotive vehicles, and, more specifically, to such grinding when performed in the more or less standard type of grinding machine in which the crank shaft to be ground is supported at each end for rotation'in the grinding machine while the grinding wheel is maintained in contact with the portion of the crank shaft being ground.

As is well known, the crank shaft is rotated during the grinding, such rotation being on the axis of the particular portion which is being ground. The flange end of the crank shaft, being the end of the crank shaft to which the flywheel of the automotive engine is attached, is mounted in the head stock of the lathe part of the grinding machine. In order to rotate the crank shaft during the grinding, the head stock in the grinding machine must not only support the flange end of the crank shaft but must be linked to the crank shaft in such manner as to cause the crank shaft and the head stock to be rotated in unison as rotation is imparted to the head stock.

In the standard type of grinding machine above referred to, the driving connection between head stock and the flange end of the crank shaft heretofore has been provided by means of an arm mounted on an off-center pin on the head stock, the arm carrying a pin which, in turn, is inserted in a bolt hole on the flange of the crank shaft. The flange of a crank shaft has a plurality of bolt holes to accommodate the bolts by which the flywheel is attached to the end of the crank shaft when the crank shaft is mounted in place in the engine. However, due to the fact that these bolt holes may vary in size for different crank shafts, this connecting driving means between head stock and crank shaft in the standard grinding machines often allows slight play in the connecting arm which re sults in slight jerks or vibration when the rotary movement of the head stock is transmitted to the crank shaft.

An object of the present invention is to provide an improved coupling between the head stock of the grinding machine and the flange of the crank shaft which will prevent any play between the two.

A related object of the invention is to provide a coupling which will be suitable for use with a crank shaft regardless of the size of the bolt holes in the flange of the crank shaft.

A further object of the invention is to provide improved coupling means for the purpose described which will be practical to use and which can be readily and easily installed.

The manner in which these objects are attained, the manner in which my improved coupler is constructed, and the manner in which it functions, will be readily understood from the following brief description in which reference is made to the accompanying drawings,

In the drawings:

Fig. 1 is a fragmentary plan view of the lathe portion of a standard grinding machine for crank shafts, showing a crank shaft mounted therein, and with my improved coupler in place between the crank shaft end flange and the head stock of the lathe;

2,772,527 Patented Dec. 4-, 1956 Fig. 2 is an enlarged plan view of the flange end of the crank shaft and adjacent head stock of the lathe of Fig. 1, together with the connected coupler;

Fig. 3 is a sectional elevation taken on line 3-3 of Fig. 2, but drawn to a larger scale; and

Fig. 4 is a perspective view of the coupler by itself.

In Figs. 1 and 2 the crank shaft is indicated in general by the reference character 10. One end of the crank shaft has the customary flange 11 to which the engine flywheel is secured when the crank shaft is in place in the engine. The crank shaft, during the grinding operation, is supported in the lathe of the grinding machine with the flange 11 adjacent to the head stock of the lathe.

As is customary, the head stock carries a plate 12 on which is mounted an off-center ofcrank-turning pin 13. Also as is customary, the flange 11 is provided with a plurality of (thus, in this case four) bolt holes 14 (Fig. 3) for the bolts which are used to secure a flywheel to the flange.

My improved coupler includes a bar 15 (Figs. 3 and 4) and a composite arm assembly 18 which is adjustably attached to one end of the bar 15. The other end of the bar 15 is provided with an aperture 16 of exactly the right size to fit the off-center pin 13 of the plate 12 of the head stock. The bar 15, in turn, carriers a pin 17 of sufliciently small diameter to be received in any bolt hole of a flange of any crank shaft. Thus, as indicated by broken lines in Pig. 3, the pin 17, by way of illustration, is assumed to be of considerably smaller diameter than the bolt holes 14 of the crank shaft flange 11 illustrated. The composite arm assembly 13, which is adjustable attached to the bar 15, includes a main bracket arm 19 and a slidably adjustable block 20 (Figs. 3 and 4). The bracket arm 19 has a longitudinally-extending slot 21, through which a clamping bolt 22 passes, the bolt 22 extending through a supporting hole in the bar 15. Thus, the position of the bracket arm 19 can be adjusted variously with respect to the bar 15 when the nut of the bolt 22 is loosened. The bolt 22, and consequently the bracket arm 19, are positioned a spaced distance on the bar 15 beyond the pin 17 and are located at the opposite end of the bar 15 from the aperture 16.

The outer end portion 19 of the bracket arm 19 is increased in thickness and also in width, and a center rod 23 is securely mounted in this end portion and extends outwardly in the same plane with the slotted portion of the arm 19. A block 20 is slidably mounted on the rod 23. A pair of side rods 24- and 25 are also similarly mounted in the end portion 19' of the bracket arm 19 and are positioned on opposite sides of the rod 23, being parallel to the rod 23. The block 20 is provided with a pair of channels 24 and 25 (Fig. 3) in which the outer ends of the rods 24 and 25 are slidable. Coil springs 26 and 27 are carried on the rods 24 and 25 respectively, and are held under compression between the outer end portion 19' of the bracket arm 19 and the block 20. The center rod 23 is threaded and carries a nut 28 by means of which the position of the block 20 with respect to the bracket arm 19 is adjusted.

The block 20 carries a pin 29 of the same diameter as the pin 17 for similarly engaging one of the bolt holes 14 of the flange 11 of the crank shaft. When the coupler is connected to the crank shaft (the coupler being carried on the off-center or crank-turning pin 13 of the plate 12 of the head stock, asshown in Fig. 2) the positions of the arm 19 and block 20 are adjusted so that when the pin 17 of the bar 15 enters one of the bolt holes 14 of the flange 11 the pin 29 of the block 20 will enter another of the bolt holes 14. The clamping bolt by which the composite arm assembly 18 is secured to the bar 15 is tightened so as to secure the bracket arm 19 rigidly to the bar 15, and finally the nut 28 is tightened. The tightening of the nut 28 will cause the pins 17 and 29 to be brought closer together to the extent that their engagement with the bolt holes 14 will permit. As a result, the pins 17 and 19 press firmly against the opposite sides of their respective bolt holes 14, as indicated in broken lines in Fig. 3, clamping the intervening portion of the flange 11 between them.

Thus, with the clamping bolt 22 tightened and with the nut 23 holding the pins 17 and 29 pressed towards each other, any play between the coupler and the flywheel flange 11 will be impossible, even though the bolt holes 14 of the flange 11 are considerably larger than the pins 17 and 29 of the coupler.

I claim:

1. In combination, a lathe having a headstock, a plate on said headstock, an eccentrically located crank pin on said plate, an automotive crank shaft mounted in said lathe for grinding, an end flange on said crank shaft, a plurality of identical bolt holes in said end flange, said end flange engaged by said headstock, a pair of members forming a composite coupler between said headstock and said flange, said members secured together near their adjacent ends in a position of angularity with respect to each other, an aperture near an end of one of said members, said aperture having the same diameter as said crank pin and engaged by said crank pin, a flangeengaging pin rigidly secured in said first mentioned memher and in engagement with one of said bolt holes, a second similar flange-engaging pin adjustably mounted in said other member and in engagement with another of said bolt holes, said flange-engaging pins being of smaller diameter than said bolt holes, means in said other member for moving said second fiangeengaging pin towards said first member, and said means so adjusted that said flange-engaging pins will be forcibly urged relatively towards each other, whereby any play between said members and said flange is prevented.

2. in combination, a lathe having a headstock, a plate on said headstock, an eccentrically located crank pin on said plate, an automotive crank shaft mounted in said lathe for grinding, an end flange on said crank shaft, a plurality of identical bolt holes in said end flange, said end flange engaged by said headstock, a pair of members forming ,a composite coupler between said headstock and said flange, means for adjustably securing said members together near their adjacent ends in a position of angularity with respect to each other, said means comprising a clamping bolt mounted near the end of one of said members and extending through a slot located in the end portion of the other of said members, an aperture near the opposite end of said first mentioned member, said aperture having the same diameter as said crank pin and engaged by said crank pin, a flange-engaging pin rigidly secured in said first mentioned member and in engagement with one of said bolt holes, a second similar flange-engaging pin adjustably mounted in said other member and in engagement with another of said bolt holes, said flange-engaging pins being of smaller diameter than said bolt holes, screw means in said other member for moving said second flange-engaging pin towards said first member, and said screw means so adjusted that said flange-engaging pins will be forcibly urged relatively towards each other, whereby any play between said members and flange is prevented.

3. In combination, a lathe having a headstock, a plate on said headstock, an eccentrically located crank pin on said plate, a crank shaft mounted in said lathe for grinding, an end flange on said crank shaft, a plurality of identical holes in said flange, said flange engaged by said headstock, a pair of members forming a composite coupler between said headstock and said flange, said members adjustably secured together near their adjacent ends in a position of angularity with respect to each other, one of said members having an aperture near the opposite end, said aperture having the same diameter as said crank pin and engaged by said crank pin, a flange-engaging pin rigidly secured in said first mentioned member and in engagement with one of said holes in said flange, a block slidaoly mounted on the opposite end of said other memher, a second flange-engaging pin secured in said block and in engagernent with another of said holes in said flange, screw means on said other member for moving said block towards said first mentioned member, and said screw means so adjusted that said flange-engaging pins will be forcibly urged relatively towards each other, whereby any play between said members and the crank shaft flange is prevented even though said flange-engaging pins are of considerably less diameter than said holes in said flange.

References Cited in the file of this patent UNITED STATES PATENTS 189,953 Niebell Apr. 24, 1877 494,310 Wensing Mar. 28, 1893 2,386,254 Meyer Oct. 9, 1945 FOREIGN PATENTS- 237,8l5 Switzerland Sept. 1, 1945 

